Punnet Squares
Calculate the Probability of Genetic Combinations
- can look at one trait or several
- includes notice of genotypes and phenotypes
- can be a diamond, circle, or square
2 to the Number of Traits for Number of Rows/Boxes
- Example: looking for 2 traits: 2 x 2 = 4
- 4 rows and 4 columns
Dominant Trait is 1st
Example: If testing for blue vs brown eyes, blue eyes are recessive. Therefore B would represent brown and b would represent blue. If the parents genotypes are Bb and BB, the probabilities would come out as
- BB
- BB
- Bb
- Bb
Because B would be dominant, it comes first.
Dihybrid Cross
- looking at two genes at once ie. hair color and eye color